Silk screen printing ink



3,086,873 SILK SCREEN PRlNTlNG INK Alexander H. Steinbruuner, 31Anniston Drive, Dayton 15, Ohio No Drawing. Filed Aug. 25, 1960, Ser.No. 51,779 24 Claims. (Ci. res-24 This invention relates to a novelink-emulsion vehicle which is adapted for silk screen printing on a baseto produce a decorative transfer sheet for heat release to an article tobe decorated and to a transfer sheet embodying said ink.

The invention also relates to a novel method of manufacturing anink-emulsion vehicle which is storage stable in a two-package system andwhich is capable of being formulated to adjustthe silk screen printingresults to variation in ambient relative humidity and temperature whileproviding excellent color reproduction, clarity and sharpness ofdefinition in the color half-tone type of printing which is transferredfrom the transfer sheet.

The invention further relates to a method of decorating and printing byusing an iron-on decal prepared with the ink-emulsion vehicle of theinvention. The transfer sheet, which heat-releases an ink-resin colordesign to another object, after heat-ironing treatment is generallytermed an iron-on" decal.

Iron-on decals, like postage stamps, have the design imprinted on areleasable base of paper, cellophane, cellulose acetate, or sheetnitrocellulose and the design comprises a thermally adhesive ink-resinsurface activated by heat applied to the back of the releasable sheetthereof to fasten it to the surface to be decorated by the transfer.

In the hands of the user, the transfer sheet is positioned in thepreselected area over the fabric and heated with an iron to transfer theink-resin dots in one or more colors. The face of the decal isfrequently protected by a thin sized paper or fabric sheet which isremovable when the decal is to be put in place.

The iron-on decals of the prior art have generally been made,heretofore, by printing with commercial printing machines, the design,usually in color, using special solid transfer ink containing wax andresin. The printing machine employed is provided with a halftoneprinting surface. The design on the decal is thus the same astypographic printing from a half-tone plate and the decal serves todeposit the design in the form of a series of small colored dots ofprinting ink-resin vehicle from the transfer sheet to the object beingdecorated. These half tone dots, therefore, take the form of a reversepattern of the design on the decal so as to provide a positive image onthe sheet or object which is to be decorated, usually a surface ofmetal, paper Woven textile or other fabric.

The ink which is used to form the half-tone dots on the conventionaliron-on decal is normally solid and becomes fluid when used with aheated letter press, litho and/ or gravure printing machine. Theprinting machine is thus used to heat the ink to elevated temperature atwhich it is molten so as to provide a suitable printing consistency inmaking the decal. The print effect from the machine is obtained,therefore, by transferring a film of the ink in which there is nopenetration to the fibers in an attempt to achieve the resultant clarityand sharpness of outline of the printed ink films after transfer from.the decal. In contrast, the emulsion ink of the invention is applied notas a film from a half-tone printing plate but as a mass over the entiresilk screen to the decal base and this mass nevertheless results in aseries of separated color dot of solid ink, releasable by heat transferto the object to be decorated.

3,@8h,373 Patented Apr. 23, 1963 ice In the conventional type of iron-ondecal made by printing, the foundation material for the pigment or dyeis usual-1y made by combining several waxes and/ or resins to design anink which will soften in the temperature range used by the printingmachine (generally :-275 F). Waxes and resins of the ink vehiclealthough selected for specific qualities, must first meet thetemperature requirements for transfer and of the printing machine andhigh melting waxes such as carnauba wax, beeswax and Montan wax aresoftened with lithographic varnish components, e.g., linseed oil or tungoil to provide proper working qualities of the ink and make it usable athigh temperature on the half-tone plate. Heretofore, parafiin was wasadded to act as a release agent for the ink mixture (see Lawrence, US.Patent No. 1,939,821) and for this purpose was used in only minorproportion so that the wax base is essentially a high melting baserather than a low melting paraffin base. The essential solvent used forthis high melting wax of the prior art is aromatic hydrocarbon. Incontrast, the basic component of the wax of the invention is paraifinWax which softens in a lower temperature range than the waxes used inthe prior art and which is effectively dissolved and dispersed in watermedium by kerosene or similar aliphatic solvent. Further, the waxcomposition of the invention completely dispenses with synthetic ornatural resins such as isobutylene polymer, gilsonite resins andphenolic resins which usually are added in the prior art to provide aproper balance of cohesion and adhesion and for desired viscosity at themelting range.

During heat transfer, the individually colored dots in the conventionaliron-on decal tend to flow into each other, giving poor colordefinition, a muddy appearance and insufiicient detail in the impresseddesign on the fabric. Thus, the results, despite the expense ofmanufacture of the decal, are considerably less than optimum for manydecorative uses of these transfer sheets and considerable efforts havebeen made to improve the transfer ink.

In contrast, the present invention uses a specially formulatedone-package or two-package aqueous wax emusion Whose printingapplication is completely independent of the heating condition of theprinting machine and which is applied in the cold by conventional silkscreen application.

The present invention, thus makes possible the adaptation of the silkscreen process for manufacture of transfers embodying multicolored inkdots. Surprisingly, the dots do not merge or run when applied as anemulsion in the cold. Heretofore, multicolored designs on painted tincans and painted sheet metal advertising special signs made cheaply bythe silk screen process have required special quick-drying paints whichin turn require special resins, solvents, driers, and drying operations.These requirements are obviated in the aqueous quick-drying emulsion ofthe invention which omits special driers or unusual drying operations.

In conventional silk screening, a decorative design or lettering orother identification mark is applied to objects by means of the silkscreens bearing the outlines of the design. The design is first made ina flexible metal, paper or similar backing by cementing a piece of silkor nylon. Nylon has replaced silk for most uses due to its highertensile strength and durability. Paint or ink in bulk is forced throughthe meshes of the fabric by means of a stiff brush or a rubber squeegeeafter the screen is placed firmly on the object, or the paint may besprayed through the screen.

The oil-in-water ink emulsion of the invention is specifically adaptedfor silk-screen printing because of the unique wax composition in theoil phase which provides a heat .releasable and heattransferable waxfilm on the transferjsheetor on. an iron-on decalcomania. The wax vcomposition in the dispersed oil phase is a mixture of a low melting,wax; an intermediate melting wax and a high melting wax, and the mixturemelts in stages throughout the range from about 125 F. to about 210 F. vI

The low melting low melt viscosity wax is preferably petroleum orparaflin wax of melting range 125-l65 F., the wider melting commercialwaxes being preferred but mixtures of slack wax with ozocerite (50/50),with gilsonite' (50/ 50) and with Utah wax (50/50) also being suitable,and is present in said mixture in a proportion of from 41-49% by weightof the total wax present.

The intermediate melting wax has a melting range of from about 142-150F. Yellow beeswax, melting point 142-149, F., white beeswax, meltingpoint 140-152 F. and Ghedda wax, melting point 141-151 F. are examplesof suitable high melt viscosity waxes which areessential in the waxmixture to provide for-high melt viscosity and high surface tensionthereby facilitating silk-screen painting in the cold and transfer ofthe wax film under hot conditions. v v I a Ihe high melting wax has amelting range of between 180-187 F. Thehigh melting wax imparts hardnessand'includes carnauba wax, melting point .180-187 F., Montan wax,melting point 165-170 E, Ouricuri, melting point 180-187" F., thesewaxes alone or in admixture with each other. V

A liquid, vegetable oil plasticizer is present with the wax mixturebeing in an amount of from about 24-30% of the total weight of said-waxand oil. q v

A hydrocarbon solvent for said wax mixture is used, said solvent havinga boiling point of from 100-250 F. constituting fromabout 44% to 52%' ofsaid oil phase, and serving as the volatile carrier for said wax andvegetable oilplasticizer. 3

A stabilizing a'gent is essential in the water phase, this agentincluding as the essential ingredient milk protein in an amount of from2-8% of said water phase .which is dispersed by an amount of about 0.1to 0.4%fof soap and. 0.05 to 0.2% .of borax to interactwith, said milkprotein as the sole alkaline. agents in saidwater phase. Thus, .in.contrast, to the convention ,oil i nva r,.pig ment emulsion whichis.specifically formulated to deposit acontinuous film of the binder byvirtue of add ing surface tension reducing emulsifying agents,theemulsion wax vehicle of the present-invention is formulatedlfor anopposite purpose to prevent forming a continuous film. The alkali metalsoap and/ or an alkali metal boratevintieract with the milk protein toprovide only limitedfsurface tension reduction. Since these constitutethe only alkaline materials for aiding dispersion of ,the milk proteinin the water phase, thealkaline emulsifying complex effectively .limitsthe fihn flow of the dispersed wax particle during silkscreen printing.There is rtainedin the oil phase a wax component having sub'stantiallyhigh viscosityand high surface tension. The deposit of discrete colordots of film by forcing the emulsion in bulk through the openings of thesilk screen remains fixed in place in the transfer sheet. The highsurface tension of the liquid dOtSl helps retainthe spacing on transfer.Also the alkali metal borate treated milk protein does' notappear tosignificantly alter the. wax melt viscosity at the high temperature usedinheat-transfer. The protein-isjeifectiye to preventcoalescence of thedeposited wax dotsinto a continuous film in the presenceof the organicsolvent whichis. alsopresent inthe oil phase. V I

The water immiscible organic liquid solvent has aboiling range of-from100-250" F. and is a good so lyent for the wax binder and vegetable oilplasticizer. Although the choice of solvent may depend to some extentupon the pigment or dye which is employed, it is prefer-red to 4 combinean aromatic or naphthenic high solvent power solvent with a parafiinsolvent, such solvents as benzene, toluene or xylene are blended withsolvent naphtha, kerosene, and white spirit. It is necessary that theamount of solvent employed vary between rather narrow limits whensubstantial amounts of cheaper low solvent power parafiin solven-ts areused, e.g., between about 44 to about 52% of the oil phase. If toolittle solvent is present, e.g., from about 25.35% of the mixture of15-25% aromatic hydrocarbon solvents and -75% of paraflin solventswiththe wax present in an amount of more than 65%, then the wax emulsionis too heavy, very difiicult to form and too thick to use in the silkscreen process. If the amount of solvent is too much, e.g., about 60%,the solvent mixture acts to promote continuous film formation and thereis not achieved the desired deposit of separate discrete and sharplydefined color dots by cold application through the silk screen.

.If minor amounts of stronger volatile solvents are added, such aspetroleum ether, carbon tetrachloride, etc., the amount of aromatic ornaphthene solvent should be reduced. Cheaper types of naphthene andparafiin solvents are preferred since they require less skill inhandling and produce, in most cases, more uniform and better silk screenprinting results. a

All of the solvents used are volatile at room or moderately elevatedtemperature and may be termed evaporative water immiscible organicliquids. In general, any combination of petroleum distillate of parafiinstructure andcoal-tar distillate of naphthene or aromatic structurehaving a wide boiling range in the range of about F. to 250 F. willprovide desirable silk screen printing results.

The essential emulsifying ingredient of the invention, the alkalinesoluble milk protein, is preferably used in the form of evaporated orcondensed milk. The protein in condensed milk may amount to not morethan 25% of its condensed solids, e.g., 100 grams of condensed milk maycontain about 8 grams solids of which about 2 grams are the essentialprotein constituent, however, there may be up to four times this amountof protein employed. In milk the protein is acidic and isbelieved toreact in the same manner as dry milk protein and casein with thealkaline borax and soap to form a more soluble protein, possiblycaseinate in the presence of milk fat which is soluble in the waterphase. The milk protein is rendered more soluble in the aqueous phase ofthe emulsions by means of .alkaline, soap, e.g., sodium oleate,potassium oleate, sodium stearate, potassium stearate, and borax. Thus,the emulsion composition may be diluted more readily. with solvent,e.g., kerosene or with water to the extent as may be required forvarious uses.

,;Other water-soluble proteins than milk protein, for example, Vgelatin, water-soluble albumins, alkali-soluble, acid-precipitablecasein and soy bean protein may be included with milk protein asdesirable ingredients in the wax phase of the emulsion but the proteinstabilizer must include milk protein as an essential ingredient.

-.,When the ink is to be used, emulsifying agents may be addedifde'sired by the printer under circumstances where a very thin coatingis wanted. Such emulsifying agents are not necessary :but when addeditis preferred to include acid, sulfuric acid esters of fatty alcohols,sulfonated castor oil, higher alkyl sulfonates, higher hydroxyalkylsulfonates, sodium a-hydroxyoctadecane sulfonate, s-ulfodicarboxylicacid ester, for example, the sodium salt of sulfo-succinic acid dioctylester, higher alkyl-aryl sulfonates, and'polyglycol ethers of fattyalcohols of higher molecular weight, such as oetyl, oleyl or octadecylalcohol, fonexample, reaction products of 15-30 molecular proportions ofethylene oxide with 1 molecular proportion of afatty alcohol. There mayalso be used emulsifying agents having a pronounced wetting action, suchas octylphenol polyglycol ether, acid sulfuric acid esters thereof, andalso dodecyl alcohol polyglycol ethers.

Particularly, emulsifying agents in these cases are:

1,6-dilauryl diglycerol Mono-abietic acid ester of triglycerolMono-stearyl glycerol Mono-cetyl ether of glycerol Mono-oleyl glycerolDi ethylene glycol mono-stearate With respect to the pigments or fillersemployed, if a white ink is desired, lithopone, zinc oxide, titaniumoxide and barium sulfate or other white pigments as desired. Venetianred, is a suitable pigment for use if a red coating is desired.

Lake pigments, such as those of the alizarine lake type, and thoseformed by the combination of a basic dye with a hetero-polyacidcontaining a plurality of radicals of phosphorus, tungsten, molybdenum,and silicon may be used especially those which are formed by thecombination of a basic dye with a phosphometal acid (phosphotungsticacids, phosphomolybdic acids, phosphotungstomolybdic acids). Alsodyestufi materials such as organic pigments anthraquinone dyes andinsoluble azo compounds may be used such as Kiton Blue A (Colour IndexSupplement, page 44) Orange II (Colour Index Supplement No. 151)Alizarin Sapphire Blue B (Colour Index No. 1054) Benzyl Green B (ColourIndex No. 667) Orange R (Colour Index No. 161) Brilliant Kiton Red B(Colour Index No. 748) Acid Violet 6B (Colour Index No. 698) Acid Green(Colour Index No. 660) Direct Fast Orange SE (Colour Index No. 326)Cotton Fast Blue 3G (Colour Index No. 503) Carbide Black ER (Co1ourIndex No. 582) Thioflavin T (Colour Index No. 815) Rhodamine B (ColourIndex No. 749) Cotton Yellow CH (Colour Index No. 365) Chlorantine FastRed 7B (Colour Index No. 278) Following is a summary of the compositionfeatures of the emulsion ink of the invention adapted to be used withthe dyestuifs and pigments indicated:

A. FILM BINDER COMPOSITION PROPORTIONS 1. WAX AND PLASTICIZERPROPORTIONS IN THE OIL PHASE Wax or Plasticizer component Range,Preferred,

Percent Percent Parafiin 30-36 33 18-22 20 18-22 20 Linseed oil 24-30 272. OIL PHASE PROPORTIONS, WAX AND HYDROCARBON SOLVENT The presentinvention is believed to be the first to provide means enabling acommercially practical cold silk screen process for effecting transfersheets for iron-on decals by providing a novel ink emulsion baseuniquely enabling the economical printing of iron-on decals and theentire elimination of the heated printing equipment which was usedheretofore. Moreover, the invention provides an improved means for coldapplication of predetermined color dots to a transfer sheet in preciselydefined relation with water soluble or water insoluble colors and in anaqueous medium so the colors can be transferred therefrom with completedefinition, clarity and uniformity as to detail. The iron-on decal thusprovided enables a better and more lasting image reproduction on fabricthan was previously possible.

The following examples, in which all of the formulae are given in partsby weight of the several materials, will serve to illustrate theinvention:

Example 1 Percent Xylol 30 Naphtha 60 Kerosene 10 The first base mixtureB has the following composition by weight:

Percent Paratlin wax 8 Beeswax 5 /2 Carnauba wax 9 Kerosene l0 Linseedoil 5 Thinner A 7 /2 Soap (soft) 10 Milk (condensed) 44 Borax l Thesecond base mixture C has the following composition by weight:

Percent Soap (soft) 7 Milk (condensed) 55 /2 Linseed o-il 7 Beeswax 3 /2Paraffin wax 7 Kerosene 20 In forming the ink base, the thinner A isfirst mixed at room temperature. The three ingredients, Xylol, naphthaand kerosene, are weighted, placed in a glass container, or itsequivalent and shaken well to effect a mixture at normal roomtemperature conditions.

The base mixture B may be prepared as follows. The proper percentages byWeight of the three wax ingredients are placed in a metal or equivalentcontainer and melted together at approximately 200 F. and allowed tocool to about F. The indicated proportion of the thinner A is then addedand stirred in to provide a mixture having a light cream consistency.Then the kerosene and linseed oil are stirred in, the whole mixturebeing effected at a temperature of approximately 150 F. The blending ofthe melted waxes and the thinner A first eliminates the possibility offormation of lumps of wax which will not pass through Woven silk andinsures an extremely smooth cream consistency of the mixture. Themixture is then allowed to cool. If desired, at this point a smallamount, up to A2 by weight, of a wetting agent, glycol mono-oleate maybe added to increase the working freedom of the waxes.

However, this is not essential to the making or usage of i thecomposition. In the event the wetting agent is added, the resultantmixture must be left to stand for at least 24 hours to permit theWetting agent to conventionally function. g

The soapand borax of the composition B are separately mixed at roomtemperature and the condensed milk stirred in to provide a producthaving a soft cream consistency. The soap, milk and borax thus mixed arethen added to the previously mixed waxes, thinner A, kerosene, andlinseed oil and the whole is blended to a fine cream consistency bybeating or stirring it vigorously with a paddle or an equivalent device.This prod-uces a completely stable emulsified product B which may bestored almost indefinitely in any climate.

The mixture C is formed by first melting the beeswax and paraffin waxtogether at a temperature in the neighborhood of 200 F. To the meltedwaxes is addeda mixture of linseed oil and kerosene in the amounts givenabove. The condensed milk and soap mixture are then added with efiicientstirring to the mixture of beeswax, paraffin wax, linseed oil andkerosene. After eflicient mixing the mixture C is brought to a lightcream consistency by continued stirring at room temperature. Theemulsified product C is completely stable in storage for an extremelylong time, e.g. 6 months or longer under the normally encounteredstorage co-nni n Each of the base compositions B and C are combined toprovide an ink base for pigmenting which is useful for an effective silkScreen printing process for producing transfer sheets and iron-ondecals. A preferred combination of the base B and C for this purposeconsists of 60% B and 40% C by weight, these proportions varying from40-75% of B and 60- 25% of C. By mixing in suitable blending equipment,an ink base is provided which will serve as a vehicle for wash out ink(water soluble ink) or permanent type dye. Depending on the climatewhere the ink base is to be employed, the composition of the ink basemay range from 40% to 75% of the base B by weight.

b The product resulting is thoroughly emulsified and on mixing of a dyetherein provides an ink which will readily flow through silk at ordinaryroom temperatures. This ink also has the characteristic of hardening onexposure to air at ordinary room temperature.

Ex'a'mpl'e II In this example pigmented types of aqueous emulsioninkcompositions are described.

The base mixture B" and the base mixture C of Example I are mixed in50/50 proportions by volume. Venetian red pigment in an amount of 42% byweight of combined B and C is carefully blended in by stirring withefiicient mechanical stirring at room temperature for 3-4 hours. The redcolored emulsion is applied by silk screen to form red colored dots on acellulose acetate film base to make an iron-on decal. A flat iron,electrically heated to 200-225 F. serves to transfer the red dots of theimage to a paper sheet.

Example III This example illustrates variations in the wax composition.

In similar manner to the preparation of Example I, thinner A, first basemixture B, and second base mixture C are mixed. The only change which ismade in the formulation is to substitute in mixture B and in mixture C,a mixture of slack wax and OZOCIlI, there being present 50 parts of eachof these waxes in the petroleum wax component. This petroleum waxmixture melted in the range of 120-160 F. Ozocerite was added in theproportion varying from 30-70 to 70-30 to the slack wax. Upon combiningthe so modified mixtures B and C as set out in Example I, an ink pigmentas in Example 11 produced satisfactory iron-on decals'oncelluloseacetate.

Similarly the petroleum wax of Example 'I was changed to a mixture ofslack wax and gilsonite, a-further embodiment was a mixture of Utah waxand slack wax. In both of these latter compositions, the gilsonite andUtah wax were used in varying proportions with slack wax from 70-30 to30-70 by weight. Similar satisfactory de cals' were produced;

A further formula was made in which the high melting wax component,carnauba wax of base B in Example I was substitutedin the same amountwith Montan wax. v Equally good results were obtained in the final decalprinted by the silk screen method.

A further formula was prepared utilizing Ouricuri wax instead ofcarnauba wax in Example I.

Still another mixture was made in which the petroleum wax component ineach oflformulas B and C is a mixture of equal parts of slack wax, Japanwax and gilsonite.

Each of these latter formulations provided excellent iron-on decals.

Example IV This example illustrates variation of the oil plasticizingcomponent. The method for'formulation is the same as in Example I,the-method of pigmentation and application of the ink by silk screenprinting is as set out in Example II. The'variation illustrated 'in thisexample is by substituting in the same proportion as set out in ExampleI, tung oil, castor oil, and a 50/50 mixture of wool fat and linseedoil.

Each of the foregoing" formulations provided satisfactory iron-onde'cals in accordance with the procedure in Example 11.

In the foregoing examples there are illustrated various wax emulsion inkformulations based upon kerosene as the essential solvent, milk proteinas the essential stabilizing agent and a vegetable oil as thenon-volatile wax plasticizer for a petroleum based wax. The petroleumwax based composition exhibits a melting range in the temperatureinterval for decal transfer by a hot iron, e.g. from to 210 F. In eachinstance of printing the discrete separate dots were formed on the decaland transferred from the decal to a receiving sheet in unimpairedcondition without loss of clarity, spacing or dimensions.

In each case the printing on the transfer base sheet, nitrocellulose,cellulose acetate, Holland cloth, at room temperature resulted in dotswhich readily dried at room temperature. Color overprinting followsconventional silk screen multicolor printing. The stability of thecombined formulawas such that it could be used within 24 hours aftermixing. The storage stability of the separate mixes B and C" is 6 monthsor longer. The lower the content of aromatic solvent (e.g. xylol orcyclic naph- -thene) and the higher the content of petroleum wax (e.g.gilsonite, parafiin, Utah wax, etc.) the better the stability of the onepackage mix. In certain cases storage stability of several weeks isobtained with the high petroleum base compositions.

The ink base provided by the invention is translucent so that any coloror type of dye may be added and there is accurate strength and colorreproduction. There is no reaction produced between the dye and theresultant ink base which will distort the true dye or pigment color inany respect.

Any conventional inexpensive paper may be used as a transfer sheet afterhavingbeen first sealed with liquid rubber or its equivalent. The silkscreen frame is placed over the coated paper and inks employing the baseof the invention may be pressed through the silk screen in the requiredpattern and onto the paper using a squeegee. No heat is involved in theapplication. The smoothness of the ink base enables the inks to befreely flowed through the screen and to be clearly and distinctlyimpressed on the paper in the required pattern. In this manner a reverseimage of the desired decal pattern is effected on the transfer sheet.This reverse image dries distinctly on the transfer sheet on ordinaryexposure to air at room temperature and the transfer sheet so formed maybe stored relatively indefinitely. When it is desired that this transfersheet be used, it may be placed over the fabric on which the image is tobe impressed with the impression adjacent the fabric. Application of thehot iron to the back of the transfer sheet effects an immediate transferof the image to the fabric in a clear and distinct fashion. A positiveimage results which has a substantial life expectancy under, ordinaryusage. All colors are reproduced in perfect registration and withsubstantial uniformity. The combination of the waxes as emulsified bythe condensed milk produces an ideal vehicle for transfer of the ink tothe fabric in a clear distinct image.

Thus the ink base of the invention provides a medium enabling a coldprocess of effecting transfer sheets for iron-on decals which isextremely inexpensive and simple to employ. This opens up a new field ofendeavor for every silk screen processer and enables him to placeimages, designs or any artistic creation on paper without need forexpensive dies and in a manner so it can be effectively applied tofabric by a simple ironing application. The process enabled by theinvention compositions expands the silk screen art to a significantdegree and it is made possible by the composition provided by theinvention.

The emulsions of the invention have been particularly described Withreference to their use in silk screen printing. However, they may alsobe advantageously employed in eflfecting spot carbon and for similarapplications. Such is comprehended as within the scope of the presentinvention.

I claim:

1. An oil-in-water ink emulsion adapted for silk screen printing toprovide a heat releasable and heat transferable film on a transfer sheetconsisting essentially of a dispersed oil phase of a wax mixture of (1)low melting, low melt-viscosity petroleum wax component, (2)intermediate melting, high melt-viscosity wax component and (3) a highmelting, medium melt-viscosity wax component, said wax mixture meltinggradually throughout the range from about 125 F. to about 210 F., saidlow melting wax component (1) melting in a range of 125- 165 F. andbeing present in a proportion of from 41-49% by weight of the total waxpresent, said intermediate melting wax component (2) melting in a rangeof from about 142-150 F., and said high melting wax component (3)melting in a range of about 180-187 F., a liquid vegetable oilplasticizer for said wax being present in an amount of from about 24-30%of the total weight of wax and oil, a volatile petroleum hydrocarbonsolvent for said plasticizer wax mixture having a boiling point of from100-250" and constituting from about 44% to 52% of said oil phase, andas a stabilizing agent for said wax, plasticizer and solvent, milkprotein in an amount of from about 28% present in said water phase,together with about 0.1 to 0.4% of alkali metal soap and 0.05 to 0.2% ofborax to interact with said milk protein as the sole alkaline agents insaid water phase.

2. An ink emulsion as claimed in claim 1 wherein said low melting waxcomponent is parafiin wax which is present in an amount of from 41-49%by weight of the total wax present, said intermediate melting waxcomponent is beeswax which is present in an amount of from 24-30% oftotal wax present, and said high melting wax component is carnauba waxwhich is present in an amount of from 24-30% of the total wax present.

3. An ink emulsion as claimed in claim 1 wherein said petroleum wax is amixture of slack wax and ozocerite.

4. An ink emulsion as claimed in claim 1 wherein said petroleum wax is amixture of slack wax and gilsonite.

5. An ink emulsion as claimed in claim 1 wherein said petroleum wax is amixture of Utah wax and slack wax.

6. An ink emulsion as claimed in claim 1 wherein said intermediatemelting wax component is Ghedda wax, said low melting wax component isparafiin wax and said high melting wax component is carnauba wax.

7. An ink emulsion as claimed in claim 1 wherein said high melting waxcomponent is Ouricuri wax and said intermediate melting wax is beeswax.

8. An ink emulsion as claimed in claim 1 wherein said high melting waxcomponent is Montan wax and said intermediate melting wax is beeswax.

9. An ink emulsion as claimed in claim 1 wherein said petroleum wax is amixture of slack wax, Japan wax and gilsonite.

10. An ink emulsion as claimed in claim 1 wherein said wax isplasticized with linseed oil.

11. An ink emulsion as claimed in claim 1 wherein said wax isplasticized with tung oil.

12. An ink emulsion as claimed in claim 1 wherein said wax isplasticized with castor oil.

13. An ink emulsion as claimed in claim 1 wherein said wax isplasticized with a mixture of wool fat and linseed oil.

14. An ink emulsion as claimed in claim 1 wherein said petroleumhydrocarbon solvent is predominantly kerosene with a minor proportion ofaromatic petroleum hydrocarbon solvent therein.

15. An iron-on decal made by silk screen printing to provide a heatreleasable and heat transferable film comprising a transfer sheetprinted with an oil-in-water ink emulsion consisting essentially of awax mixture of (1) low melting, lo-w melt-viscosity petroleum waxcomponent, (2) intermediate melting, high melt-viscosity wax componentand (3) a high melting, medium melt-viscosity wax component, said waxmixture melting gradually throughout the range from about 125 F. toabout 210 F., said low melting wax component (1) melting in a range of125-165 F. and being present in a proportion of from 41-49% by weight ofthe total wax present, said intermediate melting wax component (2)melting in a range of from about 142-150 F., and said high melting waxcomponent (3) melting in a range of about 180-187 F., a liquid vegetableoil plasticizer for said wax being present in an amount of from about24-30% of the total weight of wax and oil, a volatile petroleumhydrocarbon solvent for said plasticizer wax mixture having a boil pointof from -250 F. and constituting from about 44% to 52% of said oilphase, and as a stabilizing agent from said wax, plasticizer andsolvent, milk protein in an amount of from about 2-8% present in saidwater phase, together with about 0.1 to 0.4% of alkali metal soap and0.05 to 0.2% of borax to interact with said milk protein as the solealkaline agents in said water phase.

16. The method of making an oil-in-water ink emulsion adapted for silkscreen printing to provide a heat releasable and heat transferable filmon a transfer sheet comprising mixing at a temperature between 100-200F. a wax mixture of (1) low melting petroleum wax component, (2)intermediate melting wax component and (3) a high melting wax component,said wax mixture melting gradually throughout the range from about F. toabout 210 F., said low melting wax component 1) melting in a range of125-165 F. and being present in a proportion of from 41-49% by weight ofthe total wax present, said intermediate melting wax component (2)melting in a range of from about 142-150 F., and said high melting waxcomponent (3) melting in a range of about ISO-187 F., adding a liquidvegetable oil plasticizer for said wax and a volatile petroleumhydrocarbon solvent having a boiling point of from 100-25 0 F thereafteradding milk protein in'water to provide' 'a total watercontentof'about41 to 50%, the milk-solids content'being- -about'6'-9% ofthe water-and adding about-0.1 to 0.4% of soap and'0.05 to 0.2%ofborax'to interact with said milk protein as the sole alkaline agentsin said water phase.

17. A method as claimed in claim 16 wherein said'rnilk protein in wateris added in the formof condensed milk and said emulsion is pigmented.

18. A method as claimedinclaim 16 wherein said milk protein in water isadded in the form of reconstituted powdered milk.

19; oil-in-water pigmented ink. emulsion adapted for silk screenprinting to providediscrete dots of heat transferable design on atransfer sheet consisting essentially of a dis'persed-o-il'pha-seconsisting of a wax mixture of;

wide melting range petroleum wax component, and higher melting hardwaxco-mponent, said-Wax mixture melting gradually throughout the range fromabout 125 F. to

about 210 F., there being present a proportion o-fi parafiin wax toprovide kerosene solubility of the entire wax mixture, a liquidvegetable oil plasticizer for said wax being present in an amount fromabout 24% up to 30% by weight of the total weight of wax and oil'and. avolatile petroleum hydrocarbon solvent for said. plasticizer wax mixturehaving a boiling point in the kerosene range and constituting about 52%to about 44% of said oil phase, a water phase, a pigment and as astabilizing agent for said wax, plasticizer and. solvent, milk proteinin an amount of from about 28% present in said water phase.

20. An oil-in-water pigmented ink emulsion. adaptedfor silk screenprinting to provide; discrete. dots of heattransferable design on, atransfer sheet consisting essentiallyof a dispersed oil phase consistingof awax mixture of wide melting range parafiin wax component, and higherconsisting of carnauha wax,,.Montan wax,- beeswax and mixtures of saidwaxes, said wax mixture :gradually melting throughout the rangeof fromabout 125 F. to about 210 F there being present-a proportionof paraflinwax to provide kerosene solubility of the entire wax mixture, a-liquidvegetablevoil plasticizer for said wax being present in an amount fromabout 24% upto 30% by Weight of the totalweight of wax and oil and avolatile petroleum hydrocarbon solvent for saidplasticizer wax mixturehaving a boiling point in the kerosene range, a water phase, apigmentand as a. stabilizing agent for said wax, plasticizer and solvent, milkprotein being present in said waterphase.

21. An. emulsion asaclaimed inclaim, 19 in which said solvent is.kerosene containing a small proportion of xylene.

22'. An emulsion as. claimed in claim 19in which there is present soap.and 'borax each in amount less than 1% to aid suspension of the oilphase.

23. An emulsion as. claimed in claim 19 wherein said pigment is. awater-soluble dyestufi.

24. An. emulsion. as .claimed; inclaim 19 wherein said pigment is awater-insoluble dyestuff.

References Cited in the file of this patent UNITED STATES PATENTSv1,954,451 Lawrence Apr. 10, 1934 1,977,680 Lawrence Oct. 23, 19341,990,193 Lohmann Feb. 5, 1935 2,044,056 Burgard- June 16, 19362,074,758 'Reynolds h, Mar. 23, 1937 2,756,874 Ericksonjet a1 July 31,1956 2,961,334 Clancy et a1. Nov. 22, 1960 1-..-:--.-:-.'-.:-.-. FOREIGNATENT 523,479 Canada Apr. 3, 1956

1. AN OIL-IN-WATER INK EMULSION ADAPTED FOR SILK SCREEN PRINTING TOPROVIDE A HEAT RELEASABLE AND HEAT TRANSFERABLE FILM ON A TRANSFER SHEETCONSISTING ESSENTIALLY OF A DISPERSED OIL PHASE OF A WAX MIXTURE OF (1)LOW MELTING, LOW MELT-VISCOSITY PETROLEUM WAX COMPONENT, (2)INTERMEDIATE MELTING, MEDIUM MELT-VISOCITY WAX COMPOENENT AND (3) A HIGHMELTING, MEDIUM MELT-VISCOSITY WAX COMPONENT, SAID WAX MIXTURE MELTINGGRADUALLY THROUGHOUT THE RANGE FROM ABOUT 125*F. TO ABOUT 210*F., SAIDLOW MELTING WAX COMPONENT (1) MELTING IN A RANGE OF 125165*F. AND BEINGPRESENT IN A PROPORTION OF FROM 41-49% BY WEIGHT OF THE TOTAL WAXPRESENT, SAID INTERMEDIATE MELTING WAX COMPONENT (2) MELTING IN A RANGEOF FROM ABOUT 142-150*F., AND SAID HIGH MELTING WAX COMPONENT (3)MELTING IN A RANGE OF ABOUT 180-187* F., A LIQUID VEGETABLE OILPLASTICIZER FOR SAID WAX BEING PRESENT IN AN AMOUNT OF FROM ABOUT 24-30%OF THE TOTAL WEIGHT OF WAX AND OIL, A VOLATILE PETROLEUM HYDROCARBONSOLVENT FOR SAID PLASTICIZER WAX MIXTURE HAVING A BOILING POINT OF FROM100-250*F. AND CONSITUTING FROM ABOUT 44% TO 52% OF SAID OIL PHASE, ANDAS A STABILIZING AGENT FOR SAID WAX, PLASTICIZER AND SOLVENT, MILKPROTEIN IN AN AMOUNT OF FROM ABOUT 2-8% PRESENT IN SAID WATER PHASE,TOGETHER WITH ABOUTT 0.1 TO 0.4% OF ALKALI METAL SOAP AND 0.05 TO 0.2%OF BORAX TO INTERACT WITH SAID MILK PROTEIN AS THE SOLE ALKALINE AGENTSIN SAID WATER PHASE.